Wet 2,4,6-trichloro-1,3,5-triazine(TCT)as an efficient catalyst for the synthesis of 2,4,6-triarylpyridines under solvent-free conditions

<正>An efficient one-pot synthesis of 2,4,6-triarylpyridines has been described.This involves the three-component reaction of aldehydes,ketones and ammonium acetate in the presence of a catalytic amount of wet 2,4,6-trichloro-1,3,5-triazine(TCT) under solvent-free condition at 130℃.     

Adducts of lanthanide β-diketonates with 2,4,6-tri(2-pyridyl)-1,3,5-triazine: Synthesis,structural characterization,and photoluminescence studies

Adducts of lanthanide β-diketonates of the general formula LnL₃(TPTZ) were synthesized and structurally characterized by single crystal X-ray diffraction [Ln = Eu³⁺, Tb³⁺, Er³⁺; L is the conjugate base of dibenzoylmethane (DBM), 1-benzoylacetone (BA), thenoyltrifluoroacetone (TTA), or 4,4,4-trifluoro-1-phenyl-1,3-butanedione (BTFA); TPTZ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine, a rigid Lewis base with a large π system]. The lanthanide ion in each of these complexes is nonacoordinate with six β-diketonate oxygen atoms and three TPTZ nitrogen atoms, forming a coordination polyhedron best describable as a monocapped square antiprism. Characteristic red, green, and near infrared luminescence was observed for the Eu³⁺, Tb³⁺, and Er³⁺ complexes, respectively. All complexes showed significantly enhanced luminescence quantum yields when compared with the corresponding aqua analogues, with one of the Eu³⁺ complexes displaying a quantum yield of 69.7% in chloroform.     

A versatile and practical synthesis of bis(indolyl)methanes/bis(indolyl)glycoconjugates catalyzed by trichloro-1,3,5-triazine

A practical and efficient electrophilic substitution reaction of indoles with a variety of aldehydes was carried out using catalytic trichloro-1,3,5-triazine (10 mol %) in acetonitrile to furnish the corresponding bis(indolyl)methanes in excellent yields. Similarly, sugar derived aldehydes gave hitherto unknown bis(indolyl)glycoconjugates in very good yields.     

A Rh(II)-catalyzed cycloaddition approach toward the synthesis of komaroviquinone

Using a rhodium(II)-catalyzed cyclization/cycloaddition sequence as the key reaction step, the icetexane core of komaroviquinone was constructed by an intramolecular dipolar-cycloaddition of a carbonyl ylide dipole across a tethered π-bond. The ylide was arrived at by cyclization of a rhodium carbenoid intermediate onto a proximal ester group. Efforts toward the preparation of the required precursor for elaboration to the natural product are discussed.     

Green chemistry approach to the synthesis of 3-substituted-quinazolin-4(3H)-ones and 2-methyl-3-substituted-quinazolin-4(3H)-ones and biological evaluation

ABSTRACT

A synthesis of two series of 3-substituted quinazolinones was performed utilizing a green chemistry approach, deep eutectic solvents and microwaves, namely. 2-Methyl-3-substituted-quinazolin-4(3H)-one derivatives were synthesized in a two-step reaction, using choline chloride:urea deep eutectic solvent (DES). 3-Substituted-quinazolin-4(3H)-ones were synthesized in one-pot one-step reaction of anthranilic acid, amines and orthoester in a microwave reactor. For the synthesis of 2-methyl-3-substituted-quinazolin-4(3H)-ones, first conventional synthesis of benzoxazinone, as an intermediate, was performed. Further, benzoxazinone in reaction with corresponding amines, in choline choline:urea deep eutectic solvent, furnished desired compounds. These procedures are based on green principles with the aim of developing synthetic routes for the potential antitumor agents. All compounds were characterized by LC/MS, ¹H NMR and ¹³C NMR spectral techniques. Compound 1 bearing trifluoromethoxyphenyl group showed promising activity against HuT-78 cell line with IC₅₀ of 51.4?±?5.1?µM.     

Studies on bis (cyclopentadienyl) titanium (IV) chelates of biologically active O-hydroxynaphthoquinone and its derivatives

A convenient method for the preparation of Cp₂Ti(L) complexes, where Cp is cyclopentadienyl and L is the conjugate base of O-hydroxynaphthoquinone or its derivatives, has been described. The new complexes have been characterized on the basis of chemical analysis, infrared and NMR spectral studies. These studies indicate that the complex is formed in 1:1 ratio and the ligand L chelates through the oxygen of the O-hydroxy group.     

Colorimetric Sensing of the Insensitive Energetic Material 3-Nitro-1,2,4-triazol-5-one (NTO) Using l-Cysteine Stabilized Gold Nanoparticles and Copper(II)

Abstract

Since conventional sensitive explosives have given rise to unforeseen accidents during storage and transport, the demand of modern armies for insensitive energetic materials is on the rise. There are very few determination methods for the most widely used insensitive energetic materials such as 3-nitro-1,2,4-triazole-5-one (NTO). Thus, the aim of this work is the development of a rapid and practical nanoparticle-based colorimetric sensor for determination of NTO. The detection principle of the sensor involved electrostatic attraction of NTO anion to the ammonium group of l-cysteine functionalized gold nanoparticles (AuNP-Cys), followed by the formation of a Cu²⁺-coordination complex between particles to result in AuNPs agglomeration. The concomitant color change was from red to violet. The surface plasmon resonance band of AuNPs at 520?nm shifted to 650?nm upon chemical reaction and agglomeration. Spectroscopic evaluation was made by taking the ratio of 650?nm absorbance to that of 520?nm, and correlating this ratio to NTO concentration. The analytical performance characteristics of this ratiometric sensor for NTO as the molar absorptivity (ε); limits of detection (LOD) and quantification (LOQ) were: ε = (8.62?±?0.29) × 10³ L mol^?1 cm^?1, LOD = 0.25?mg L^?1, and LOQ = 0.85?mg L^?1. The sensor was applied to various energetic material mixtures containing 2,4,6-trinitrotoluene, hexahydro-1,3,5-trinitro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, and tetryl. Additionally, the possible interference effects of commonly found soil ions such as Cl^–, NO₃^–, SO₄^2–, PO₄^3–, Mg²⁺, Ca²⁺, Na⁺, and K⁺ were studied. The proposed method was statistically validated against a literature liquid chromatography–tandem mass spectrometry (LC/MS-MS) method.     

A bio-oriented anthranilic acid catalyzed synthesis of quinazolin-8 (4H)-one derivatives: Evaluation by green chemistry metrics

An environmental friendly synthetic route has been investigated for the synthesis of quinazolin-8 (4H)-one derivatives in the presence of anthranilic acid as a catalyst. The zwitter ion formed in course of reaction may a play key role in the desired transformations leading good to excellent yields. Evaluation of the present protocol by green chemistry metrics demonstrated that it is highly efficient and eco-compatible.     

Ethylp-(2-methyl-3-oxopropyl)- andp-(2-methyl-3-oxo-1-propenyl)benzoates: preparation and use in the synthesis of biologically active derivatives ofp-(nor-polyprenyl)benzoic acids

Novel ways for preparing the title compounds have been developed. Saturated (1) and unsaturated (2) aldehydoesters, which are easily accessible by a Pd-catalyzed reaction of ethyl 4-bromobenzoate with methallyl alcohol and aldol condensation of ethyl 4-formyl-benzoate with propanal, respectively, are strategically advantageous intermediates for the synthesis. The results of thein vitro assays of some of the synthesized compounds are compared with the known data on their pharmacological effectsin vivo.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2126–2129, December, 1993.     

3-Amino-5-mercapto-1,2,4-triazole-functionalized Fe3O4 magnetic nanocomposite as a green and efficient catalyst for synthesis of bis(indolyl)methane derivatives

A core–shell Fe₃O₄@silica magnetic nanocomposite functionalized with 3-amino-5-mercapto-1,2,4-triazole (Fe₃O₄/SiO₂/PTS/AMTA) was prepared using Fe₃O₄ with silica layer, and its surface was modified with 3-amino-5-mercapto-1,2,4-triazole. The novel synthesized magnetite nanocomposite was characterized using various techniques. The catalytic activity of Fe₃O₄/SiO₂/PTS/AMTA was demonstrated in the synthesis of bis(indolyl)methane derivatives under solvent-free conditions. Some of the bis(indolyl)methane derivatives were synthesized through one-pot, three-component reaction of 1 mol of various benzaldehydes or ketones with 2 mol of indole in the presence of Fe₃O₄/SiO₂/PTS/AMTA in good to excellent isolated yields. In addition, the catalyst could be recovered and used for several reaction runs without loss of catalytic activity. The stability of recycled catalyst was investigated. This method has some advantages including experimental simplicity, good to excellent yields, solvent-free conditions and stability and reusability of the catalyst.     

A green development of Bernthsen 9-substituted acridine synthesis in the absence of solvent catalyzed by p-toluenesulphonic acid (p-TSA)

Abstract

Bernthsen reaction has been carried out under microwave irradiation in the presence of p-TSA (10 mol%) as catalyst in a solventless reaction to provide 9-substituted acridines. In the present report, time economy and better yields as compared to conventional Bernthsen reaction are described.     

Triphenylarsenic(V) and -antimony(V) derivatives of multidentate Schiff bases: synthesis,characterization, and antimicrobial activities

Equimolar reactions of Ph _n M(OPr ⁱ )₂ (where M?=?As and Sb) with Schiff bases [OHC₆H₄CH=N(R)OH] in benzene solution yield organoarsenic and -antimony derivatives, (where M?=?As and Sb; n?=?1 and 3; R?=?–CH₂CH(CH₃)–, –(CH₂)₃–, –(CH₂)₂–, and –C(CH₃)₂CH₂–). All these derivatives have been characterized by elemental analyses and molecular weight measurements, and structures have been proposed on the basis of IR, NMR (¹H and ¹³C), and FAB-mass studies. Schiff bases and their corresponding organoantimony derivatives have been screened for antimicrobial activity against Aspergillus flavus (fungus) and Escherichia coli (bacteria).     

A facile, microwave-assisted synthesis of novel optically active polyamides derived from 5-(3-methyl-2-phthalimidylpentanoylamino)isophthalic acid and different diisocyanates

5-(3-Methyl-2-phthalimidylpentanoylamino)isophthalic acid as a novel aromatic diacid monomer was prepared in three steps. In the first step, phthalic anhydride was reacted with l-isoleucine in acetic acid solution, and the resulting imide acid was obtained in high yield. In the second step, treatment of this imide acid with excess thionyl chloride gave aliphatic acid chloride in good yield. In the last step, this acid chloride was reacted with 5-aminoisophthalic acid to provide novel bulky chiral aromatic diacid monomer. The direct polycondensation reactions of this diacid with several aromatic and aliphatic diisocyanates such as 4,4′-methylenebis(phenyl isocyanate), toluylene-2,4-diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate were carried out under microwave irradiation. In order to compare this method with classical heating, the polymerization reactions were also performed under solution polycondensation conditions. The polymerization reactions occurred rapidly under microwave conditions and produced a series of novel optically active polyamides (PA)s containing pendent phthalimide group, with good yields and moderate inherent viscosities of 0.17-0.60 dL/g. Some of the new PAs showed good solubility and are readily soluble in organic solvents. The resulting macromolecules were characterized by FT-IR, specific rotation, and representative ones by ¹H NMR, elemental and thermogravimetric analyses (TGA).     

Manganese(II) tetrasulfophthalocyanine covalently supported on natural silk: A new highly active catalyst for synthesis of benzoxazepine derivatives in water

Natural silk as a biodegradable, biocompatible, renewable, green and abundant biomaterial was used as a support for chemical immobilization of a water‐soluble manganese(II) complex with a phthalocyanine ligand possessing covalent binding ability. The prepared manganese(II) tetrasulfophthalocyanine complex supported on natural silk revealed efficient catalytic activity and reusability for the synthesis of benzoxazepine derivatives in water at room temperature.     

Nanomagnetically modified vitamin B3 (Fe3O4@Niacin): An efficient and reusable green biocatalyst for microwave‐assisted rapid synthesis of 2‐amino‐3‐cyanopyridines in aqueous medium

Superparamagnetic nanoparticles of modified vitamin B₃ (Fe₃O₄@Niacin) represent a new, efficient and green biocatalyst for the one‐pot synthesis of 2‐amino‐3‐cyanopyridine derivatives via four‐component condensation reaction between aldehydes, ketones, malononitrile, and ammonium acetate under microwave irradiation in water. This new magnetic organocatalyst was easily isolated from the reaction mixture by magnetic decantation using an external magnet and reused at least six times without significant degradation in the activity. The catalyst was fully characterized by FT‐IR, XRD, SEM, VSM, UV–Vis, DLS and EDS. Excellent yield, very short reaction time (7–10 min), operational simplicity, easy work‐up procedure, avoidance of hazardous or toxic catalysts and organic solvents are the main advantages of this green methodology which makes it more economic than the other conventional methods.     

Green polymer chemistry: Precision synthesis of novel multifunctional poly(ethylene glycol)s using enzymatic catalysis

This paper gives an overview about enzyme catalysis, and reports the precision synthesis of multifunctional poly(ethylene glycol)s using this green chemistry approach. Specifically, vinyl acrylate was transesterified with tetraethylene glycol (TEG) and a PEG with DP_n = 23, and then (HO)₂–TEG–(OH)₂ and (HO)₂–PEG–(OH)₂ were synthesized by the Michael addition of diethanolamine to the acrylate double bonds. These structures will serve as the core of novel dendrimers designed for drug delivery applications.